Sterile tissue access system

ABSTRACT

A tissue access system used for tissue ablation without open surgery includes a distally open tube-like hollow organ ( 4 ) with a proximally introduced handle piece ( 6 ) that comprises a through channel ( 7 ) in axial alignment with the hollow organ and an infusion fitting ( 9 ) that opens into the through channel for supplying a liquid or gaseous medium. An energy guide ( 16 ) such as a laser light guide or a catheter housing such light guide is arranged in the hollow organ and fixed in a sealing manner towards the outside using a seal ( 8 ) provided in the through channel. The energy-releasing zone of the energy guide is located in an energy-transparent section of the hollow organ. The medium, introduced into an annular flow channel between the energy guide or catheter and the hollow organ, serves as coolant for the energy-releasing zone of the energy guide and as heat transport medium in the tissue and can also function as an ablation agent and as contrast agent for inspection using imaging techniques. The tissue access system according to the invention is highly effective with minimal strain on the patient, is of simple design and can easily be handled and permits control of tissue treatment using imaging techniques.

[0001] This invention relates to a sterile tissue access system thatincludes an energy guide at the end of which an energy-releasing zone isprovided for tissue ablation without open surgery and that is shieldedby, and arranged in, a non-ferromagnetic, heat-resistant, and at leastdistally energy-transparent tube-like hollow organ.

[0002] When using diagnostic imaging techniques such as magneticresonance tomography, computer tomography, ultrasound and the like, itis not only possible to show the position, size, and shape of pathologicchanges in the body but to carry out operations using needles, probes,and catheters without open surgery. An increasingly successful operationof this type is tissue ablation that is primarily used to eliminatetissue from spots that are difficult to access, i.e. to kill specifictissue areas that are subsequently slowly resorbed by the surroundingtissue.

[0003] As an alternative to mechanical ablation where the quantity ofablated tissue is limited by the small diameter of the medicalinstruments, liquids that cause tissue ablation can be administered,however with the disadvantage that such harmful liquids might flow intohealthy tissue and damage it.

[0004] And finally these known devices can be used for small-diametertissue access to kill tissue by generating thermal energy or byfreezing. While cryoablation requires powerful probes and respectivelylarge-diameter needles and catheters and is therefore limited in use,the disadvantage of thermal ablation is that it interferes with magneticresonance tomography, an imaging technique that is used verysuccessfully for controlling the ablation process.

[0005] It has proven beneficial for tracking and controlling thermalablation using magnetic resonance tomography and for killing thetargeted tissue area completely without damaging healthy tissue to uselaser light as an energy source.

[0006] The respective tissue access systems, however, have caused thefollowing problems when this method was used: Easy access to the tissuewithout unnecessary damage or injury to the patient, mechanical andthermal sensitivity of the diffusing body (energy-releasing zone) at thedistal end of the laser light guide, risk of fourth-degree burning ofthe tissue in the vicinity of the diffusing body, exact positioning ofthe ablator in the tumor tissue, observation and accurate control of theablation process regarding the completeness of the ablation, and gentletreatment of the healthy tissue. Access to the tissue is particularlyproblematic with sensitive tissue such as the central nervous system orthe lung. As the diffusing body is fragile, steps must be taken toprotect it and to prevent unnecessary mechanical strain. Fourth-degreetissue burn can be prevented by effective heat dissipation from thevicinity of the diffusing body. And finally any interference ofdiagnostic imaging techniques has to be prevented by appropriate methodsand materials.

[0007] A respective laser application device is described, for example,in DE 196 14 780 A1. It comprises a puncture needle to be introducedinto the body through the hollow shaft of which a guide wire is insertedafter removing a mandrin. After the puncture needle has been taken off,a guide tube with a hollow inner mandrin in its hollow shaft is insertedvia the guide wire. Subsequently, the guide wire and the hollow mandrinare removed. The guide tube that is open at its distal end comprises aT-piece at its proximal end via which local anaesthetics, lubricants, ortissue adhesives can be supplied. Moreover, this laser applicationsystem includes a distally connected sheath catheter that houses a laserlight guide after its inner mandrin is removed.

[0008] The device consists of a plurality of parts and has a complexdesign so that a multitude of steps is required to access the tissue.The patient to be treated is also put under severe strain because thediameter of the guide tube to be introduced into the respective tissuearea is rather large. While the hollow catheter protects the diffusingbody, i.e. the energy-releasing zone of the light guide, from mechanicalstrain and damage, the laser can only be operated at a low output (up toapprox. 6 watts). If the output is higher, the heat available at the tipof the sheathing catheter becomes too concentrated, which results infourth-degree burns and destruction of the system.

[0009] While a cooling system provided according to DE 197 02 898 A1using another sheathing catheter to prevent this disadvantage enables arelatively high laser output of up to 30 watts, the coolant that flowsdirectly past the diffusing body of the laser light guide and isdischarged outside dissipates a considerable portion of the thermaloutput from the tissue that will not be available for treatment. Inaddition, such systems are not suited for specific applications such asthe central nervous system and the lungs or constitute risks anddisadvantages for the patient due to the large coolant quantity required(60 ml/min) and the accordingly large cross sections of the probes andcatheters and the large-diameter puncture openings.

[0010] It is therefore the problem of this invention to provide anapparatus for tissue ablation that can be controlled using imagingtechniques, is of simple design and easy to handle while being highlyeffective with minimal effect on the patient as well as versatile.

[0011] This problem is solved according to the invention by a tissueablation through energy supply apparatus having the characteristicsaccording to claim 1 wherein the energy form may vary and includephysical and chemical processes in the tissue.

[0012] The subordinate claims and the preferred embodiments presented asexamples herein disclose further important characteristics andadvantageous improvements of the invention.

[0013] In other words, it is the concept of this invention that a handlepiece is mounted to a distally open, tube-like hollow organ that has theshape of a needle or catheter and houses the respective energy guide,and that said handle piece is equipped with an infusion fittingconnected to a through channel that is axially aligned with said holloworgan. A seal arranged in the through channel ensures airtight sealingof the respective tissue. A liquid or gaseous medium for cooling isinfused directly or indirectly via the injection fitting into theenergy-releasing zone of the energy guide and from there into thetissue. In this way, all the heat emitted from the energy guide isavailable for the ablation process while the energy-releasing zone iscooled at the same time so that the risk of damaging the tissue byfourth-degree burns due to excessive heat emission is excluded.

[0014] The liquid or gaseous medium infused into the tissue may alsohave a toxic or therapeutic effect that enhances the ablation process,alleviate pain and/or function as a contrasting agent for exact controland monitoring of the process using imaging techniques.

[0015] The tissue killing performed with the device according to theinvention is therefore complete but still gentle, in particular withregard to adjacent healthy tissue. Another important advantage is thatthe hollow organ in the embodiments of the invention can be sealedtowards the outside when introducing it into the tissue area to betreated that ingression of air that could have a detrimental effect onthe patient is excluded. In addition, only small-diameter punctureopenings are required. The energy-releasing zone of the energy guide isprotected and cannot be destroyed. In addition, the apparatus thatconsists of a small number of parts only is also easy to handle. Tissueaccess can be achieved with just one puncture, which makes the unitsuitable for biopsies without repeated puncturing or replacement ofparts that are in contact with the body. The device according to theinvention can therefore be used effectively but without risks anddisadvantages for the people to be treated.

[0016] Preferable agents for infusion with the apparatus according tothe invention to enhance tissue ablation are ethanol, acetic acid oracetic acid diluted in water, dimethyl sulfoxide which also improveslight transmission, or dimethyl formamide.

[0017] Anaesthetics for local pain relief or cytostatics,radiopharmaceuticals and other tumor therapeuticals that prevent localand regional tumor recurrences can be infiltrated directly into theaffected tissue for treatment purposes.

[0018] Preferably infused contrasting agents are iodinated compounds,paramagnetic or superparamagnetic compounds, or agents with small gasbubbles as used for X-ray methods or in magnetic resonance tomographyand ultrasound diagnostics.

[0019] Gases used to enhance the ablation process are carbon monoxideand toxic gases that have a similar effect. In addition, medical gasessuch as carbon dioxide, oxygen, xenon, or anaesthetic gases can besupplied via the needle or the distally open catheter.

[0020] The dosage of necrosis-enhancing agents is 0.1 to 5 ml/min duringand 0.5 to 50 ml/min before and after thermal tissue ablation.

[0021] In a first embodiment, the tube-like hollow organ designedaccording to the invention is a plastic needle in which the energy guideis arranged, and its energy-releasing zone is immediately surrounded bythe supplied medium. Also, a distally closed or open and flushablecatheter that houses the energy guide can be introduced into this needlewith a media connection. Its outer diameter must be considerably smallerthan that of the needle to provide the cross section required for theflow of the medium supplied to the needle. If the catheter is closed,the energy-releasing zone that has to stay in the needle is only cooledindirectly.

[0022] According to the invention, the energy-releasing zone of theenergy guide is arranged in an area of the hollow organ(s) that does notimpede the energy and heat effect on the tissue, i.e. there is noimpermeable material in the needle or catheter that would resist theheat effect or energy release. Energy transmission may also be achievedby perforating the needle or catheter wall. Needles and catheters, atleast in the area of the energy-releasing zone, are preferablyheat-resistant for the temperature range to be expected and transparentto energy to the extent that at least 50% of the energy generated cantransfer to the tissue. When using a needle that is lessenergy-transparent or not energy-transparent at all, the needle end thatprotects the energy-releasing zone is positioned in such a way that theneedle does not obstruct the energy release into the tissue.

[0023] In another embodiment, the hollow organ according to theinvention is a catheter that directly houses the energy guide and thatis inserted into a needle of simple design with a seal arranged at itsproximal end. In this case, the supplied medium is directly applied tothe energy-releasing zone of the energy guide within the catheter.

[0024] Materials used as needle or catheter material are energy andlight transparent plastics such as PTFE (teflon), PEEK (polyetheretherketone) or polyamide that show sufficient strength even at smallwall thicknesses of 0.02 to 0.5 mm and in a diameter range of 2 mm.Alternative materials for the needles are non-ferromagnetic metals suchas titanium, in which case the distal end of the catheter has to bepositioned accordingly in the tissue to ensure energy release.

[0025] In an aspect of the invention, an adjustable stop is provided atthe outside perimeter of the needle to limit the depth of the puncturewhen the needle is inserted or when the patient moves during thetreatment.

[0026] According to another characteristic of the invention, a viscoussealing agent is contained in the respective needle to prevent theingression of air.

[0027] Embodiments of the invention are explained in greater detailbelow with reference to the drawing that shows an enlarged view of theapparatus for tissue ablation. Wherein:

[0028]FIG. 1 shows a mandrin with a proximally mounted handle

[0029]FIG. 2 shows a needle open at both sides that houses the mandrinand is filled by it, with a proximally mounted handle piece featuring aninfusion fitting and a sealable axial through channel;

[0030]FIG. 3 shows a distally connected catheter with a handle and witha seal located in its axial through channel;

[0031]FIG. 4 shows another mandrin with a proximally mounted handle foranother needle shown in FIG. 5;

[0032]FIG. 5 shows a needle with a proximally mounted handle in which athrough channel is arranged flush with the needle;

[0033]FIG. 6 shows a distally open catheter with a proximally mountedhandle piece comprising a lateral infusion fitting for gas or liquidsupply and an axial sealable through channel;

[0034]FIG. 7 shows the needle according to FIG. 2 with a distallyconnected catheter according to FIG. 3 inserted into it into which anenergy guide can be introduced;

[0035]FIG. 8 shows the needle according to FIG. 5 with a catheteraccording to FIG. 6 inserted into it wherein the liquid or gaseousmedium is conducted to the tissue directly via the energy-releasing zoneof an energy guide to be positioned in the catheter and wherein thepositioning of this catheter is indicated by a marking on it.

[0036] The mandrin 1, 1′ according to FIGS. 1 and 4 is hard to bend andcomprises a tip 2, 2′ and a short handle 3, 3′ at its proximal end. Themandrin 1 is slightly longer than the respective needle 4, 4′ accordingto FIGS. 2 and 5 so that its tip 2, 2′ protrudes from the distal end ofthe needle into which the mandrin can be fitted in a gastight manner. Ifthe energy-releasing system stays in the needle, the distal end of theneedles 4,4′ or the complete needles consist of energy-transparent,heat-resistant material. An adjustable stop 5 is attached to the outerperimeter of the needle 4,4′ to limit puncture depth.

[0037] In a first embodiment according to FIGS. 1 and 2, the needle 4 ofa design that is energy-transparent at least at its distal end isintroduced into the tissue to be killed using the mandrin 1 that islocated in the tube-like hollow space of the needle. An airtight sealindependent of the actual seal 8 can be achieved by filling the hollowspace of the needle 4 with a sterile pharmaceutical oil so that, forexample, air is prevented from entering into the thorax during tissueablation carried out in the lung. To exclude any ingression of air intothe pleural cavity, the mandrin 1 is only removed from the needle 4 whenthe distal end of the needle 4 is positioned in the respective tissue.After taking out the mandrin 1, a commercially available light guide(energy guide) 16 with a diffusing body (energy-releasing zone) at itsdistal end (not shown) is inserted into the needle 4 via the axialthrough channel 7 of a handle piece 6 mounted to the needle 4 so thatthe sensitive diffusing body is located a few millimeters before theproximal opening of the needle and thus is protected from destruction.The laser light guide 16 is fixed in operating position in the throughchannel 7 of the handle piece 6 using a packing ring 8 (or a conduitgland, not shown) and sealed with regard to the exterior.

[0038] A cooling liquid is applied to the diffusing body at an infusionspeed of 0.1 to 2 ml/min via an infusion fitting 9 that is attached tothe side of the handle piece 6 and opens into the through channel 7.This prevents fourth-degree burns of the tissue in the vicinity of thediffusing body due to excessive heat. In addition, the cooling liquidthat also serves as a heat transport medium is conducted to the tissueso that the heat the diffusing body generates becomes effective in thetissue and is not lost. The cooling liquid can also be designed as anablation agent and/or contrast medium. Gas can be introduced into theneedle instead of a liquid, however this eliminates the cooling effect.

[0039] As shown in FIGS. 3 and 6 through 8, tissue ablation can also becarried out using a laser light guide located in an additional catheter10, 10′ inserted into the needles 4, 4′.

[0040] As FIG. 3 shows, the catheter 10 may be distally closed andproximally equipped with a handle piece 11 that comprises an axialthrough channel 12 and a seal 13. This catheter 10 is slid into theneedle 4 after removing the mandrin 1 when the needle 4 has beenproperly placed in the respective tissue. The outer diameter of thecatheter 10 is smaller than the inner diameter of the needle 4. Thus ahollow space with an annular cross section is created between the needle4 and the catheter 10. The diffusing body of a laser light guide 16 tobe inserted into the catheter 10 according to FIG. 7 is protected withinthe catheter 10 and is fixed and sealed from the outside by a seal 13located in the handle piece 11. The catheter 10 that protrudes into theneedle 4 is sealed from the outside by the packing ring 8 in the handlepiece 6 and does not stretch beyond the distal opening of the needle 4when inserted. Its distal end, like that of the needle 4, consists of anenergy-transparent, heat-resistant material. Once again as describedabove, cooling liquid and, optionally, ablation and/or contrast liquidare indirectly conducted to the diffusing body and directly to therespective tissue section via the infusion fitting 9 in the handle piece6 and the annular hollow space between the catheter and the needle.

[0041] Another embodiment shown in FIG. 8 is a combination of themandrin 1 shown in FIG. 4 and the needle 4′ shown in FIG. 5 into which acatheter 10′ according to FIG. 6 is inserted after the needle has beenintroduced into the tissue and the mandrin 1 has been removed. Theneedle 4′ proximally comprises a handle piece 6′ with a through channel7′ and an adjustable stop 5′. The catheter 10′ is longer than the needle4′ but comprises a marking 14 where the two distal ends of the needleand the catheter are flush. The catheter 10′ is sealed and fixed in theneedle 4′ using a conduit gland (not shown). In this case, the catheter10′ is proximally equipped with a handle piece 11′ that is designed likethe handle 6 of the needle 4 shown in FIG. 2 and comprises a throughchannel 12′ with a seal 13′ as well as an infusion fitting 15 for thedirect supply of a liquid or gaseous cooling, ablation, and/or contrastagent to the diffusing body (energy-releasing zone) of a laser lightguide (energy guide) inserted into the catheter 10′ and to the tissue tobe treated. The fitting 15 (9) is preferably a Luer lock connectionwhile an annular packing ring with a screw-on crimped connection isprovided as the seal (8, 13, 13′). Before the energy guide 16 isactivated, the needle 4′ is pulled back from the tissue to the stop onthe handle piece 11′ so that the distal end of the catheter 10′ projectsfrom the needle 4′ beyond the end of the energy-releasing zone of theenergy guide and does not obstruct the energy release into the tissue.The tissue access system according to the invention is to be explainedin greater detail below by comparative tests in bovine liver. Theperformance of the principle according to the invention is compared tothat of the state of the art (DE 197 02 898 A1).

[0042] The function of these systems is based on the application ofhigh-energy laser light is to heat up the tissue which results inprotein coagulation. The size of the tissue zone heated up depends onthe power of the laser light (wattage) and on the fact thatfourth-degree burning of the tissue in the vicinity of theenergy-releasing zone is undesirable as it destroys the zone byoverheating. The energy-releasing zone of the light guides is cooled toprevent overheating and fourth-degree burns. The state of the art isrepresented by DE 197 002 898 A1. The system comparison below istherefore based on systems with coolant supply and discharge.

[0043] Typical use (Power Limit): DE 197 02 898 A1 Present inventionCharacteristic Somatex Power Mikrokath applicator Watts (max.) 25 15Cooling, ml/min 60 0.75 Discharge of recirculation into the tissuecooling liquid

[0044] Comparative tests were run with both systems using fresh bovineliver; the heated zone and the basically harmless but undesirableoverheating are easily identifiable after cutting the tissue open bylight discoloration (protein coagulation) and blackening, respectively.

[0045] Materials:

[0046] 1.) Somatex Power laser application set, direct-flow cooling at60 ml/min, outer diameter approx. 3 mm according to manufacturersspecifications.

[0047] 2.) Mikrokath according to DPA 101 01 143.1, infusion cooling,outer diameter 1.37 mm (tests no. 1-3) or 1.80 mm (tests no. 4-6).

[0048] 3.) For both systems: A13-0540 Mikrodom applicator by HüttingerGmbH, Umkirch, or H-6111-T3 diffusor tip laser guide connected toDornier Fibertom by Dornier Medizin Laser GmbH.

[0049] Method:

[0050] The respective applicator systems are placed deep inside thebovine liver, the light guide is inserted, laser irradiation is carriedout under the conditions specified. Then the liver is cut open inparallel to the path the light guide is conducted and the lightdiscoloration due to protein coagulation is measured. The tests denoted“P1” through “P6” (see Table 1) refer to treatment with the SomatexPower applicator set, the ones denoted “1” through “6” (see Table 1) totreatments using the Mikrokath. The coagulation volume was calculatedfrom the long and short axes of the lightly discolored coagulationellipsoids. The central zone frequently shows undesirable blackening(carbonization) which prevents further heat diffusion. TABLE 1 Testoverview Coolant Additional Coagulation Light Power Duration Energy flowtreatment using volume No. guide [W] [min] [kJ] [ml/min] the needle [ml]Blackening P1 Hüttinger 30 10 18.0 60 25.6 ++ P2 Hüttinger 25 10 15.0 6014.4 ++ P3 Dornier 25 10 15.0 60 14.1 + P4 Dornier 25 15 22.2 60 41.9+++ P5 Dornier 25 20 30.0 60 28.5 ++ P6 Dornier 30 20 36.0 60 63.6 ++++1 Hüttinger 12 20 14.4 0.50 18.0 ++ 2 Hüttinger 12 20 14.4 0.50initially 2 ml 25.6 + of saline 3 Hüttinger 12 20 14.4 0.50 2 ml of air15.3 none after 0/5/10/ 15 minutes 4 Dornier 12 20 14.4 0.50 35.3 + 5Dornier 15 20 18.0 0.75 38.5 + 6 Dornier 17 20 20.4 0.75 45.3 +++

[0051] Findings and Conclusion:

[0052] Despite the smaller dimensions of the Mikrokath and itsconsiderably lower laser power, surprisingly, coagulation zones of asimilar size are obtained as with the Somatex Power applicator. It isassumed that the intense coolant flow of the Somatex system dischargessome of the energy from the tissue. It is as astonishing that there isno more extended central tissue blackening when using the Mikrokathalthough the coolant flow is reduced to 2%. The system according to theinvention is as powerful as prior art but considerably simpler indesign, easier to handle, leaves only minor puncture damage and is alsosuitable for pulmonary metastases.

List of Reference Symbols

[0053] List of reference symbols  1, 1′ Mandrin  2, 2′ Tip of 1, 1′  3,3′ Handle  4, 4′ Needle  5, 5′ Adjustable stop  6, 6′ Handle of 4, 4′ 7, 7′ Through channel of 6, 6′  8 Seal of 6  9 Infusion fitting of 610, 10′ Catheter 11, 11′ Handle of 10, 10′ 12, 12′ Through channel of11, 11′ 13, 13′ Seal of 11 14 Marking 15 Infusion fitting of 11′ 16Energy guide (laser light guide)

1. A sterile tissue access and treatment system that includes anon-ferromagnetic, heat-resistant, and distally open as well asenergy-transparent tube-like hollow organ for housing a mandrin, or anenergy guide that can replace said mandrin and is provided with anenergy-releasing zone at its free end, with an infusion fitting formedia supply to the tissue being molded or connectible to said holloworgan, characterized in that an annular flow channel is formed betweenthe energy guide (16) or a catheter (10, 10′) housed therein and theinner wall of the hollow organ (4, 4′) for direct or indirect conductingof a coolant over the energy-releasing zone and for direct supply ofsaid coolant that subsequently functions as a means of heat transportand/or other infusion media to the tissue during tissue treatment. 2.The tissue access and treatment system according to claim 1,characterized in that the hollow organ is a needle (4) that on itsproximal end comprises a handle piece (6) with an infusion fitting (9)as well as a through channel (7) and a seal (8) for indirect inserting,sealing, and fixing the energy guide (16).
 3. The tissue access andtreatment system according to claim 2, characterized in that a distallyconnected catheter (10) with a proximally arranged handle piece (11) inwhich a through channel (12) with a seal (13) for inserting, sealing,and fixing the energy guide (16) is provided, the outer diameter ofwhich is smaller than the inner diameter of the needle (4) to form theannular flow channel and the distal end of which does not project beyondthat of the needle (4) can be introduced into the needle (4).
 4. Thetissue access and treatment system according to claim 3, characterizedin that the catheter (10) consists, at least in the section that housesthe energy-releasing zone of the energy guide (16), of a heat-resistantand energy-transparent material and in that the needle (4), at least inthis section, consists of an energy-transparent material.
 5. The tissueaccess and treatment system according to claims 1 or 2, characterized inthat the tube-like hollow body is a needle (4′) with a handle piece (6′)with a through channel (7′) into which a distally open catheter (10′)with a proximally mounted handle piece (11′) can be inserted, saidcatheter (10′) comprising a through channel (12′) with a seal (13′) forinserting, sealing, and fixing an energy guide (16) and an infusionfitting (15) for supplying a coolant or other infusion media directlyvia the energy-releasing zone of the energy guide to the tissue.
 6. Thetissue access and treatment system according to claim 5, characterizedin that the catheter (10′) is longer than the needle (4′) and comprisesa marking (14) for positioning its distal end relative to the distal endof the needle (4′).
 7. The tissue access and treatment system accordingto any one of claims 2 through 6, characterized in that the seal (8, 13,13′) in the through channel (7, 7′, 12, 12′) of the handle piece (6, 6′,11, 11′) is an adjustable packing ring with a screw-on crimpedconnection.
 8. The tissue access and treatment system according to anyone of claims 2 through 6, characterized in that a conduit gland isprovided as a seal (8, 13, 13′).
 9. The tissue access and treatmentsystem according to any one of claims 1 through 8, characterized in thata stop (5, 5′) that can be adjusted in longitudinal direction is mountedto the needle (4, 4′) to limit puncture depth.
 10. The tissue access andtreatment system according to any one of claims 1 through 9,characterized in that a sterile pharmaceutical sealing liquid isprovided for sealing off the annular flow channel between the needle andthe mandrin or catheter, respectively, to prevent air from entering theorgan to be treated.
 11. The tissue access and treatment systemaccording to any one of claims 1 through 10, characterized in that theneedles and catheters consist of a material that is heat-resistant up toat 200° C.
 12. The tissue access and treatment system according to anyone of claims 1 through 10, characterized in that the needles andcatheters consist of a material that is heat-resistant up to at 300° C.13. The tissue access and treatment system according to any one ofclaims 1 through 12, characterized in that the energy-transparent needleand catheter material is also permeable to sound and infrared light oflonger wave length.
 14. The tissue access and treatment system accordingto any one of claims 1 through 13, characterized in that a mandrin (1,1′) with a distal tip (2, 2′) that projects from the needle (4, 4′) andcomprising a proximal handle (3, 3′) for removing the mandrin is fittedgastight into the needle (4, 4′).
 15. The tissue access and treatmentsystem according to any one of claims 1 through 14, characterized inthat the energy guide (16) is designed for supplying laser light,infrared radiation, short-wave sound, or vapor.
 16. The tissue accessand treatment system according to any one of claims 1 through 15,characterized in that the coolant and heat transport medium forsupporting tissue ablation consists in completely or in part of dimethylsulfoxide or ethanol or acetic acid or dimethyl formamide.
 17. Thetissue access and treatment system according to any one of claims 1through 15, characterized in that iodinated or paramagnetic orsuperparamagnetic compounds or compounds containing fine gas bubblesthat at the same time act as a contrast agent are used as a coolant andheat transport medium.
 18. The tissue access and treatment systemaccording to any one of claims 1 through 15, characterized in thattherapeutic agents containing cytostatics, anaesthetics, or agentsregulating the blood flow are used as other infusion media.
 19. Thetissue access and treatment system according to any one of claims 1through 15, characterized in that gases containing carbon dioxide,oxygen, xenon, and narcotic or toxic gases with a necrosis-enhancingeffect are to be used as infusion media.